A ubiquitous form of optical fiber cable consists of a glass optical fiber coated by a protective polymeric layer, often referred to as a buffer layer. The glass optical fiber is typically composed of a silica-based glass core, surrounded by a silica-based glass cladding.
In many operations involving such optical fiber cables, it is necessary to remove a section of the buffer in order to expose a section of the underlying glass fiber. Various chemical and mechanical methods have been proposed for performing such removal. However, practical experience has shown that it is difficult to remove the buffer without affecting the glass fiber in some manner that degrades its strength.
In fact, only a few methods of buffer removal are known that leave the fiber strength substantially unimpaired. (The fiber strength referred to here is typically the tensile strength, as measured by pull tests in which the fiber tension is increased to the breaking point.) All of these methods involve the use of hot sulfuric acid or other chemical agents to soften or remove the polymeric coating.
Hot sulfuric acid is often disadvantageous because it requires special handling procedures and constitutes a chemical safety hazard, both in case of contact with persons and objects, and in case of fume inhalation. Moreover, disposal of sulfuric acid in industrial settings may pose a danger to the environment. These disadvantages also apply to the use of organic solvents, such as methylene chloride, as buffer removers.
Thus, there remains a need for a method of buffer removal that is free of chemical safety hazards and is friendly to the environment, but substantially maintains the strength of the optical fiber.